Concrete comprising galena ore aggregate, calcium aluminum hydraulic binder and standard aggregates



March 16, 1955 THICKNESS REOUIRED TO REDUCE RADIATION IN HALF D. A. JACKSON 3,173,884 CONCRETE COMPRISING GALENA ORE AGGREGATE, CALCIUM ALUMINUM HYDRAULIC BINDER AND STANDARD AGGRRGATES Filed July 1s, 1962 ALL sAND e. GRAVEL '5 F I G. I

o sAND e GRAvEL+ (lay/J GALENA 'z TmcKNESS ALL MAGNETITE gg MAGNET|TE+ (|2i2/,) GALENA g5 2-0 MAGNETITE (25%) @ALENA 2 a MAGNETrrE +(5o%) @ALENA l l l l x ITIO |60 |80 ZOO 220 240 260 280 300 CONCRETE POUNDS PER DENs|TY cuelc FooT COMPUTED 3 MEV.

HALF DATE THIS REPORT THICKNESS INCHES I MEV.

l 1 l I 140 ISO |80 200 220 240 260 280 CONCRETE POUNDS PER DENSITY CUBIC FOOT INVENTOR DAVID A. JACKSON SY/MQW ATTORNEY 3,173,884 CONCRETE COMPRISING GALENA ORE AG- GREGATE, CALCIUM ALUMINUM HYDRAU- LIC BINDER AND STANDARD AGGREGATES David A. Jackson, 651 E. 119th St., Chicago, Ill. Filed July 13, 1962, Ser. No. 209,758 9 Claims. (Cl. 252-478) This invention relates in general to a specialconcrete best described as of a high density type, because it is of United StatesA Patent O a higher specific gravity than the usual concrete, but

more particularly it relates to an improved radiation shielding using galena ore, which has -a very high specific gravity with a sized aggregate and a suitable cement as a Ibinder which has many high and superior quality characteristics compared with those which are presently used in concretes for high density purposes.

This concrete has an important use in the nuclear energy i industry Where a large scale production may lbe' required as a result of the use of nuclear reactors, particle accelerators, X- land gamma ray therapy radiation and radioactive materials in providing shielding material for the protection of operating personnel `against the biological hazards of such radiation. Several government agencies and industrial concerns are also proposing plans and materials for fall-out protection chambers utilizing a high density concrete of this type which is adapted to` be used in the building of these chambers and other structures for shielding purposes. l

The principal objects of the vpresent invention are therefore to provide a high density concrete which has an in-l creased specific 4gravity, considerably more than the specic gravity of any 'concretes now currently used; to mprove the radiation shielding properties against radiation and radio-active materials; to alford means for providing a uniform quality or homogenity of the mass; to provide an improved substitution for other concrete materials which hitherto has been diicult or impossible; to provide a concrete of this type which is also fast-setting in comparison with other concretes and with the requirements therefor by the Atomic Energy Commission; to provide a concrete in which the immediate setting strength is attained in much fewer days than is ordinarily required and in which the nal setting strength is greater than many shielding specifications; to effect a greater space saving not only of the aggregate materials themselves, but also of the final building structure, the space which it occupies and the shipping and storage space which it saves by means of such reduction; and to the great number of economies which result in the use of this cement; not only inthe saving of space, but also in the amountof labor in erecting the forms, .in shipping the material, in storing the material, and in the actual cost thereof.

Other objects of the invention will appear in the specitication and will be more apparent from the accompany-- ing drawings in which lFIG. 1 represents ,a chart in which the thickness required to reduce radiation in half is compared with the density of the concrete in pounds per cubic foot and |FIG. 2 is a chart inwhich the thickness required to reduce radiation in half is compared with the concrete density in pounds per cubic oot and compared with outside curves for gamma ray energies of 1.17 million electronic volts and 1.33 million electronic volts respectively.

The present materials include some of whichrthe specic gravity and prices are given for the purposes of comparison, and is not limited with galeria ore to an aggregate such as magnetite, or calcium aluminate hydraulic binder cernents such as Lumnite,I and water. As'a specific concrete, and in variations thereof, the present high density material has many unique advantages.

DENSITY 'In this consideration, the 'specicgravity is calculated or obtained =by dividing the mass in cubic feet by 62.4, the weight of one cubic foot of. water. Thelapproximate specific gravities of a number of materialsl are included to show their relative differences when included in a particular mixture as hereinafter sc etnforth:A

Table" I SPECIFIC GRAVITY In supplying any aggregate, aquantity of different sizes are furnished, and the following Table II contains an approximate analysis of the proportions of different' materials which are contained, for example, in severali'mportant aggregates. i

In the following table, the gradation of the different in'- gredient's,v galeria, magnetite and sand and gravel may be taken as given. In usingdense'aggregates, the addition of galena will obviously increase the density and cut down the whole or half thickness required; it is not restricted only to the heavy aggregates, but can be u sed with ordinary sand and gravel aggregates and with other cements, where certain specific requirements are desired, such as setting time and compression strength, and where availability of materials are concerned. f

In considering these ingredients, it is necessary to take certain nes with the so-called coarse aggregate, and for the above mixtures, the approximate percentages of the different sizes composing the aggregates are set forth in .frauen 3 SAMPLE MIxTUREs In the following examples, magnetite, sand and gravel are mixed with dierent percentages of galena ore by weight, which will show the results obtained for the different mixtures in Table III.

Table lll Concrete Mixes*-Mix number 1 2 3 4 5 6 Idenlcationt: t l t t a ena o a aggrega e percen by weight so 12% 121/5 o o Other aggregates, percent 1 50 l 75 1 87% 2 871/5 l 100 2 100 Cement (Lumnite), pounds 564 564 564 564 564 564 Galena 3, 090 1, 395 660 440 Magnetite Fines 120 1, 300 2, 250 2, 67 Maguetlte Coarse 2, 970 2, 895 2, 375 2, 675 Sand 1, 250 1, 340 Gravel 1, 820 1, 870 Water 392 383 380 300 330 300 Absolute Volume, cubic loot Cement.. 2. 87 2.87 2. 87 2.87 2.87 2. 87 Galena../. 7. 09 3. 23 1. 58 Magnetlte Fines 42 4. 61 7. 98 Magnetite Coarse 10.36 10. 20 8. 38 Sand G el W12-1?; 6. 28 6. 15 6. 10 4. 81 5. 30 4. 81 Weight per cubic loot, pounds, wet.--. 264 242 232 162 229 151 Compressxvsl Strength, pounds per uare c Sql day 1, 180 1,315 3, 840 4, 390 4, 050 3, 545 3 days .ETW 2. 310 3, 260 5, 685 5, 985 5, 625 5, 805 i b or tion cee e en s er Liiiiif s I f--- .884 .340 .335 .24o .293 .20s Hall thickness, inches l. 78 2. 0l 2. 04 2. 85 2. 33 3. 32

Cubic Yard Proportions-Welghts Materials, Absolute Volume in Cubic Feet.

1 Magnetite. 2 Sand and gravel.

These different combinations of ingredients will provide sufficient points to locate a curve A in FIG. 1, in which concrete density in pounds per cubic foot and measured from 140 to 280 pounds forms the base of the graph with the thickness required to reduce radiation in half as the altitude measured on a vertical line from the base, from 1.5 inches to 3.5 so that the necessary mixture for producing in one-half Wall thickness in inches may be read directly on the vertical line.

That this curve is substantially in accordance with the accepted practice in determining the wall half thickness, is perhaps more clearly set forth in FIG. 2 in which the data of this curve is introduced between the known curves for one mev. (million electronic volts) and 3 mev. so that the data obtained from this curve is approximately for 250 mev. and therefore entirely in accord with the density required for high density concrete at the Argonne National Laboratory for U.S. Energy Commissioner.

STRENGTH At the time of set-ting up these mixes, a 12 x 12" x 1" slab was cast and submitted to a testing laboratory to determine the absorption coeflicients using Cobalt 60. This has two gamma ray energies of 1.17 million electron volts and 1.33 mev. respectively. These were calculated to half thickness from the relationship:

Tl/z :.693/11, in which T1/1=1/2 thickness u=absorption coecients FIG. 2 illustrates the relationship of this data from the literature (Concrete for Radiation Shielding, E. J. Callan, ACI Journal, vol. 50, September 1953, pp. 17-44). The curve for this data is approximately where it may be expected; that is, between that obtained from gamma ray energies of 1 and 3 mev.

A closer look at this data in FIG. l wherein it is shown that the galena causes reduced one-half thickness as compared to equal density of all magnetite. The all magnetite test shows about one-quarter inch more thickness to reduce the radiation in half.

SPEED OF SETTING From Table III, it is noted that the compressive strength in pounds per square inch of the 121/2 galena, magnetite mixture was 3840 pounds within one day after casting, and that the compressive strength after three days for this same mixture was 5685 pounds per square inch, both well Within the minimum requirements for high density concrete.

It will also be observed that by using this galenamagnetite mixture, about three times as much density can be obtained as in the use of ordinary concrete. The galena mixture thus can be made up to have much greater shielding characteristics than any other dense aggregate or mixtures as shown by the accompanying graphs in FIGS. l and 2.

UNIT COST In a galena concentrate at the mine of approximately content, cost may be $100.00 per ton, or $5.00 more with delivery within 500 miles of approximately $5.00 more per ton, and since a 121/2 of galena results in a reduction in the amount of concrete of approximately 45% to 50% when added to ordinary concrete, and a 20%- 30% reduction in volume in using magnetite and other aggregates for a saving ofthe material used.

Where space is a factor, the reduction to the halfthickness necessary permits availability of the usable room for building, as well as for storage.

By referring to FIG. 1 for SAND & GRAVEL, a wall thickness of approximately 3.3 is required at approximately cubic feet, while sand and gravel with 121/2 of galena ore requires only a wall of 2.7" at about cubic feet, which is a saving of 151/2 in the wall thickness with only 10% increase in weight. An all magnetite mixture, according to FIG. l would require a wall thickness of 2.35 against an 871/2% magnetite content and about 229 cubic feet of density, or a 121/2% galena ore mixture would require the Wall thickness of about 2.05 for a concrete density of 232 cubic feet, thus resulting in a saving of .30" or 12.7% in wall thickness, or a gain of 3 pounds per cubic foot and 1.3 %in weight.

The following aggregates may be obtained at approximately the prices shown per ton at the locality of use:

Table IV 12%95 0F GALENA Sand and gravel. $5.00 at site. Magnetite 19.00 Ferro Phosphorus-- 90.00 Ilmenite Thus it is seen that a l21/2% increase in the present cost of high density concrete using galena and magnetite resulted in a price savings alone from 20-50%, with the Ilmenite and Ferro Phosphorus mixture. Where structural members are to be protected by sheet or brick lead, it seems evident that a homogenous cement mixture using a 121/2 galena mixture can approach the required shielding alone as the percentage additions are increased in a manner consistent with a maximum for compressive strength.

CONCLUSION Since half thicknesses of walls can be reasonably computed in inverse proportion to density, a comparison is made in FIG. 2 with a testing company who used a Cobalt 60 source, where the energies of the 3 mev. graph and a one mev. graph compare favorably with the actual line between them which may be calculated as approximately 2.40 meV.

The actual tests of the middle curve in this FIG. 2 fell almost exactly within the range estimated by the computed results from the American Concrete Institute Publication on Concrete for Rod Shielding, published 1962.

No diiculty was encountered in the workabilty of the concrete using the various percentages of galena with other high density aggregates. Since the one-half thickness of a shielding concrete is in inverse proportion to its density, it is obvious that galena with a gravity of approximately 7.50 may be used with many other minerals, enhancing their protective qualities.

It is also noted that the ore itself may be ground to oatation fneness and used straight in those areas where a preformed container is in a protective position.

While the use of galena ore in different proportions has been described in some detail, approximately the best results were obtained with the ingredients and percentages of mixtures herein shown and described, but the invention should not be limited exactly to mixtures as many Variations of these proportions may be made without departing from the spirit and scope of this invention.

I claim:

1. Extra high density concrete for radiation shielding having high structural strength, comprising galeria ore aggregate in combination with calcium laluminate hydraulic binder cement, and standard aggregates.

2. Extra high density concrete for radiation shielding, in accordance with claim 1, in which the galena ore aggregates are homogenous throughout the concrete, increased proportions of this ore compared with standard aggregates correspondingly increasing density and radiation shielding and high structural strength of a wall structure in which the galena ore is contained.

3. An extra high density concrete for radiation shielding having high structural strength, which comprises magnetite, galena ore, calcium aluminate hydnaulic binder cement and water.

4. Extra high density concrete for radiation shielding, in accordance with claim 3, in which a wall made of galena ore and a standard density aggregate and with calcium aluminate hydraulic binder cement has a one-half thickness as compared with regular ore 4and regular cement which decreases proportionally as the ratio of the galena ore aggregates increases.

5. An extra high density concrete for radiation shielding, and having high structural strength, according to claim 3, comprising aggregates of magnetite (Fe304), galena ore (PbS), calcium ialuminate hydraulic binder cement (Ca3Al4SO4) and water (H2O) all intimately mixed and allowed to set.

6. An extra high density concrete for radiation shielding and high structural strength, according to claim 5, in which a mixture of 871/2 magnetite aggregates and 121/2 galeria ore aggregates, by weight has a weight per cubic foot of 232 pounds, a compressive strength in one day of 3840 pounds per square inch, and in three days of 5685 pounds per square inch.

7. An extra high density concrete for radiation shielding and high structural strength, according to claim 5, in which a one-half thickness of wall with galena ore lis blended with magnetite, in comparison with equal density of all magnetite and requires approximately one-quarter of an inch less thickness to reduce the radiation one-half.

8. An extra high density concrete for radiation shielding and high structural strength, according to claim 7, in which the linear absorption or radiation is l2 percent les-s when 121/ percent of galena ore is mixed with magnetite than when an all magnetite mixture is used resulting in a reduction of space, volume and cost to obtain an equivalent result.

9. Extra high density concrete for radiation shielding, having high structural strength, including galeria ore aggregate in combination with other aggregates, a calcium aluminate hydraulic cement binder, and water, in which the specific gravity per unit square foot is materially raised by the galena ore, resulting in reduced amount of concrete to effect predetermined shielding, Where by saving in material, high structural capacity for building and storage, and reduction in unit cost is obtained.

References Cited by the Examiner UNITED STATES PATENTS CARL D. QUARFORTH, Primary Examiner. 

1. EXTRA HIGH DENSITY CONCRETE FOR RADIATION SHIELDING HAVING HIGH STRUCTURAL STRENGTH, COMPRISING GALENA ORE AGGREGATE IN COMBINATION WITH CALCIUM ALUMINATE HYDRAULIC BINDER CEMETN, AND STANDARD AGGREGATES. 